Muffler



July 27, 1937. G. A. KINGSLEY MUFFLER Filed April 5, 1955 \\\\\\\\\\\Nwi\\ -A Patented July 27, 1937 UNITED STATES PATENT OFFICE i MUFFLEB.

Application April 5, 1935, Serial No. 14,848

1z Claims. (C1. rs1-4s) The present invention relates to improvements in noise suppression devices and more particularly to exhaust muillers for internal combustion engines.

As its principal objects, the invention is directed to increasing the noise suppression in sound wave attenuating types of muiliers generally having relatively telescoping shells, the inner shell providing, at least in part, a through passage for the exhaust gases. In this type of muffler, to obtain compactness, the through passage in some constructions may be broken up into sections and the gases pass longitudinally back and forth as shown in my copending application, Serial No. 14,850, filed April 5th, 1935. Muiilers of this type have the advantage that effective back pressure against the ilow of the exhaust gases does not become objectionable at high engine speeds.

In muiller constructions of the aforesaid type, the inner shell constituting the main passage for the gases is generally in communication with embracing chambers constituting resonators or acoustic wave filters. Communication with these chambers is generally effected by simple circular perforations formed in the inner shell although it has been heretofore suggested to alter the configuration of such perforations slightly to improve the degree of noise suppression as disclosed in the patent to Oldberg, No. 1,938,973.

It has been found that perforations heretofore provided in the inner shell of the aforesaid type of mufiler results in the creation of objectionable high pitched or whistling noises and it is the primary object of the present invention to provide perforations which will eliminate entirely or at least greatly diminish such noises. A further object is to provide perforations which not only will eliminate whistling but which at the same time will impart a whirling action to the gases passing through the inner shell increasing the degree of noise suppression as compared with similar muiller structures differing only in the conguration of the perforations in the inner Shell.

Other objections and advantages of this invention reside in the details of construction and arrangement of parts to be more fully developed by the following description and accompanying drawing, in which Fig. 1 is a broken sectional view of a muiiler embodying the features of the invention,

tional views of modified perforation structures.

'In general the present invention comprises a muffler structure of the aforesaid type having a perforated inner shell embraced by longitudinally spaced chambers. Elongated slots in lieu 5 of conventional circular perforations are provided in the inner shell. These slots are preferably angularly disposed with reference to the longitudinal axis of the shell. Also the configuration and position of these slots is such that the 10 flow of gas breaks over sharp or pointed corners at the leading ends of the slots and preferably over similar corners at the trailing ends of the slots. It has been found that slots of such a character obviate whistling noises heretofore l5 created by the passage of the exhaust gases in such muffler constructions. Also it is the present theory that the angularly disposed slots impart a whirling action to the gases passing through the inner shell, accounting for the increase in noise suppression. 20

Referring specifically to the drawing, the muiiler structure I0, chosen to illustrate the principles of the invention, comprises an outer shell I2, an intermediate shell I4 and an inner shell I6. In this type of structure the inner shell I6 constitutes a straight through passage for the exhaust gases; the outer and inner shells define chambers constituting acoustic wave filters or resonators. Baiiles I8 and 2|! concentrically position the shells I4 and I6 Within the outer shell I2; the baffles I8 form chambers 22 between the shells I2 and I4 while the baiiies 20 form chambers 24 between the shells I4 and I6. Generally there is no communication between the chambers 22 and-24 through the bafiles I8 and 20, although 3" in some constructions it may be found desirable to perforate either the baiiles I8 or the baiiles 20, or all of them.

Referring to Fig. l the inner shell I6 is provided With a plurality of angularly disposed elon- 0 gated perforations 26 opening into the longitudinally spaced chambers 24. As shown, the perforations 26 are in the form of elongated slots having a pair of opposed sides 28-30 angularly disposed with reference to the axis of the shell I6 and opposed sides 32-34 parallel to the axis of the shell I6. This results in providing a sharp corner for the gas to break over at the leading and trailing ends of the perforations. This would be equally true if the sides 32-34 were normal to the sides 28--30 or slightly curvilinear to facilitate the punching operation. It is to be understood that the angularity, width and length of perforations and longitudinal grouping and posi- 55 5. A muiiler of the type described comprising an outer shell having inlet and outlet openings, an inner shell through which the gases are directed, a chamber defined between said shells constituting an. acoustic wave filter or resonator, and elongated perforations dened in said inner shell communicating with said chamber and the interior of said inner shell, said perforations presenting sharp corners at the leading ends thereof and their sides throughout their entire length being non-perpendicular to the flow of the gases.

6. A muier of the type described comprising an outer shell having inlet and outlet openings, an inner shell through which the gases are directed, a chamber defined between said shells constituting an acoustic wave filter or resonator, and elongated perforations defined in said inner shell communicating with said chamber and the interior of said inner shell, said perforations presenting sharp corners at the leading and trailing ends thereof and their sides throughout their entire length being non-perpendicular to the iiow of the gases.

7. A muiiler of the type described comprising A means dening a passageway through which the exhaust gases are directed, elongated slots deiined in said means to effect communication with an area of said structure embracing at least a portion of said means, said slots being angularly disposed throughout their lengths and having their sides non-perpendicular to the general direction of the W of gas through said passageway.

8. A muffler of the type described comprising means defining a chamber into which the exhaust gases are directed, elongated slots defined in said means to effect communication with an area of said structure embracing at least a portion of said means, said slots being angularly disposed throughout their lengths and having their sides non-perpendicular to the general direction of the flow of gases into said chamber.

9. A mufller of the type described comprising means defining a chamber into which the exhaust gases are directed, elongated slots defined in the general surface of said means to efl'ect communication with an area of said structure embracing at least a portion of said means, said slots having certain opposed sides thereof angularly disposed to the general direction of the flow of gases into said chamber and certain other sides parallel to the flow.

10. A muffler of the type described comprising means defining a chamber into which the exhaust gases are directed, elongated slots defined in said means to eiect communication with an area of said structure embracing at least a portion of said means, all the sides of said slots being nonperpendicular to the general direction of the flow of gases into said chamber.

11. A muliier of the type described comprising an outer shell having inlet and outlet openings for exhaust gases, an intermediate shell, and an inner shell constituting a passageway between said openings, bailles dividing the space between said shells into chambers, and means providing communication between the chambers dened by said intermediate shell with said outer shell and said inner shell, said means including elongated slots dened in said inner shell.

12. A muffler of the type described comprising an outer shell having inlet and outlet openings for exhaust gases, an intermediate shell, and an inner shell constituting a passageway between said openings, baflies dividing the space between said shells into chambers, and means providing communication between the chambers defined by said intermediate shell with said outer shell and said inner shell, said means including elongated slots angularly disposed with reference to the general direction of the iiow of gases through said inner shell.

GEORGE A. KINGSLEY.

DISCLAIMER A. Kingsley, Jackson, Mich. MUFFLER. latent dated July n Disclamer filed July 30, 1938, by the assignee, Hayes Industries,

uc. Hereby enters this disclaimer to claim l1. ieial Gazette August 30, 1938.]

DISCLAIMER 2,088,296.Geor e. A. Kingsley, Jackson, Mich. MU-FrLnn. Patent dated July 27, 1937. isclaimer filed August 31, 1939, by the assignee, Hayes Industries,

Inc.

Hereby enters this disclaimer, to wit: It is hereby -disclaimed from the scope of claims 4, 5, 6, and 10 any and all muiiier construction exce t those in which the perforations in the inner shell are disposed in the major c shell b y which they are dened; so-called louver t ear surface of the inner e of perforations formed Iby deiiect1ng[ ortions of the inner shell radiall outwarbeing specifically disclaimed.

cwl Gazette September 26,193.9. 

